1. Field of the Invention
The present invention relates to novel allosamine derivatives and to an antifungal composition or chitinase inhibitor comprising the same as an effective ingredient.
2. Discussion of the Background
Chitin is the main component of the cell wall of fungi. G. W. Gooday and A. Trinci, Symposia of the Society for General Microbiology, 30, 207-251, (1980). It is believed that balanced synthesis and decomposition of chitin occurs during repeated division and proliferation of fungi. G. W. Gooday et al., "Chitin in Nature and Technology," pp. 83-91, Edited by R. A. A. Muzzarelli et al., Plenum Press, New York, (1986). On the other hand, chitin is the main component of the cuticule of insects and it is also known that synthesis and decomposition of chitin is subtly controlled during the course of ecdysis and growth of insects. K. J. Kramer et al., "Comprehensive Insect Physiology Biochemistry and Pharmacology" vol. 3, p. 75, Edited by G. A. Kerbut and L. I. Gilbert, Pergamon Press, Inc., New York, (1985).
It is known that biosynthesis and decomposition of chitin are regulated mainly by two enzymes: chitin synthase and chitinase, respectively. Thus, it is expected that inhibitors of these enzymes could lead to new types of antifungal agents or insect growth regulators (insecticide). In fact, polyoxin, which is an inhibitor of chitin synthase, has been used as an antifungal agent in agricultural applications. Inhibitory activity against ecdysis of insects was also reported in vivo. E. Cohen and J. E. Cashida, Pestic. Biochem, Physiol , 17, 301-306, (1982).
On the other hand, as inhibitors against chitinase, only allosamidin has been found heretofore. S. Sakuda et al., J. Antibiotics, 40, 296-300, (1987). Allosamidin strongly inhibits endo-type chitinase derived from insects and is thus expected to become a useful insecticidal or acaricidal agent. Japanese Patent Application Laid-Open No. 62-207294. However, allosamidin shows a weakly inhibitory activity against chitinase derived from fungi, so it is not an effective antifungal agent.